title: Rectification and stability of a single molecular diode with controlled orientation.
abstract: In the molecular electronics field it is highly desirable to engineer the structure of molecules to achieve specific functions. In particular, diode (or rectification) behaviour in single molecules is an attractive device function. Here we study charge transport through symmetric tetraphenyl and non-symmetric diblock dipyrimidinyldiphenyl molecules covalently bound to two electrodes. The orientation of the diblock is controlled through a selective deprotection strategy, and a method in which the electrode-electrode distance is modulated unambiguously determines the current-voltage characteristics of the single-molecule device. The diblock molecule exhibits pronounced rectification behaviour compared with its homologous symmetric block, with current flowing from the dipyrimidinyl to the diphenyl moieties. This behaviour is interpreted in terms of localization of the wave function of the hole ground state at one end of the diblock under the applied field. At large forward current, the molecular diode becomes unstable and quantum point contacts between the electrodes form.
authors.affiliation: Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Ismael
authors.initials: I
authors.lastname: Díez-Pérez
authors.forename: Joshua
authors.initials: J
authors.lastname: Hihath
authors.forename: Youngu
authors.initials: Y
authors.lastname: Lee
authors.forename: Luping
authors.initials: L
authors.lastname: Yu
authors.forename: Lyudmyla
authors.initials: L
authors.lastname: Adamska
authors.forename: Mortko A
authors.initials: MA
authors.lastname: Kozhushner
authors.forename: Ivan I
authors.initials: II
authors.lastname: Oleynik
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D004553:Electric Conductivity; D004566:Electrodes; D008958:Models, Molecular; D008968:Molecular Conformation; D011743:Pyrimidines / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D011743:Pyrimidines; C030986:pyrimidine